USA Today reported that Obama officiated the ceremony for Stephanie Rivkin and Joel Sircus. One attendee posted a video of Obama reciting vows into a microphone with the caption "Holy Moly. That moment when Michelle Obama officiated at your [cousin's] wedding."

ADVERTISEMENT

The Instagram post was later deleted, but not before TMZ published it.

USA Today reported that Obama's connection to the couple comes through the bride, whose parents both have ties in politics.

The former first lady is expected to attend voter registration events in Las Vegas and Miami this week. Obama is serving as a co-chair of When We All Vote, a nonprofit initiative aimed at increasing voter turnout.

Obama is set to go on a monthlong book tour later this year to promote her new memoir, "Becoming." The arena tour kicks off in Chicago on Nov. 13, with seats and VIP packages fetching high prices.